Dynamic magnetic information storage or retrieval – Head – Magnetoresistive reproducing head
Reexamination Certificate
2011-06-07
2011-06-07
Heinz, A. J. (Department: 2627)
Dynamic magnetic information storage or retrieval
Head
Magnetoresistive reproducing head
Reexamination Certificate
active
07957107
ABSTRACT:
A current-perpendicular-to-the-plane (CPP) magnetoresistive sensor has an antiparallel free (APF) structure as the free layer and a specific direction for the applied bias or sense current. The (APF) structure has a first free ferromagnetic (FL1), a second free ferromagnetic layer (FL2), and an antiparallel (AP) coupling (APC) layer that couples FL1and FL2together antiferromagnetically with the result that FL1and FL2have substantially antiparallel magnetization directions and rotate together in the presence of a magnetic field. The thickness of FL1is preferably greater than the spin-diffusion length of the electrons in the FL1material. The minimum thickness for FL2is a thickness resulting in a FL2magnetic moment equivalent to at least 10 Å Ni80Fe20and preferably to at least 15 Å Ni80Fe20. The CPP sensor operates specifically with the conventional sense current (opposite the electron current) directed from the pinned ferromagnetic layer to the APF structure, which results in suppression of current-induced noise.
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Carey Matthew J.
Childress Jeffrey R.
Maat Stefan
Smith Neil
Berthold Thomas R.
Heinz A. J.
Hitachi Global Storage Technologies - Netherlands B.V.
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